° 1919 J Saunders, Song of the Ruby-crowned Kinglet. 525 



GEOGRAPHICAL VARIATION IN THE SONG OF THE 

 ' RUBY-CROWNED KINGLET. 



BY ARETAS A. SAUNDERS. 



Variation in bird song may be individual, local, seasonal, or 

 geographical. Individual variation is by far the commonest form, 

 and is well illustrated in the Song Sparrow (Melospiza mclodia), a 

 bird whose song seems to hold the same general characteristics 

 everywhere throughout its range, and yet is so variable that no 

 two individuals ever sing exactly alike. Local variation may be 

 found in many species. I have he,ard greater differences in the 

 songs of Field Sparrows (Spizclla pusilla) in two Connecticut 

 localities, not more than twenty miles apart, than there is between 

 the average Connecticut bird, and those of Pennsylvania or Ala- 

 bama. Seasonal variation is well illustrated in the Blue-winged 

 Warbler (Vermivora pinus), the differences between the early and 

 late songs of this species being well known. True geographical 

 variation, however, seems to be much rarer than the other forms. 

 Pycraft states that such variation "has often been denied, but 

 nevertheless . . . would seem to be true." * In my own experience 

 there has come but a single certain case, that of the Ruby-crowned 

 Kinglet (Regulus calendula). 



I have already published some facts concerning this variation 

 (Auk, XXVIII, p. 48, and Condor, XIV, p. 31), but wider studies 

 since then have led me to believe the fact worthy of description 

 in a more extended article. In general, there is a distinct, cer- 

 tain, and constant difference between the songs of the Kinglets 

 migrating through eastern United States, and undoubtedly breed- 

 ing in eastern Canada, and those breeding in the northern Rocky 

 Mountains. The complete geographical limits of each form of 

 song I am unable at present to work out. I have observed the 

 eastern song in Vermont, Massachusetts, Connecticut, New York, 

 New Jersey, Pennsylvania, and Alabama, and on the part of a few 



1 A History of Birds, p. 166. 



